There are plenty of festivals and special occasions in the craft beer world, but some days are especially significant. This Saturday is Zwanze Day, when one of the world's most unusual Belgian beers will be available at just 36 locations around the globe. Sixteen of those venues are in the United States, and California is host to two. At noon that day, a keg of Cantillon Zwanze -- a rhubarb lambic -- will be tapped at The Trappist in downtown Oakland. At exactly the same time, these special kegs will be opened for a simultaneous global toast in 34 other locations -- everywhere except Japan, where it will be 5 a.m.

The museum brewer

Brasserie Cantillon is more than just a Belgian brewery. It's also a working museum -- the Brussels Gueuze Museum -- where traditional beer has been brewed the same way since the brewery was founded in Brussels in 1900 by Paul Cantillon. They make an ancient type of beer known as lambic beer, that includes Gueuze, Kriek and Faro, and which is made with wild yeast that spontaneously ferments beer made with raw wheat, malted barley and old hops. Because the very air in the brewery contains the wild yeast, the building is never cleaned for fear of disturbing the microclimate, which would destroy the yeast that has been feeding on the beer there for more than 100 years.

Advertisement

The first time I visited the brewery in Brussels, they explained that we were quite literally stepping back in time, because the air in the brewery has been unchanged since 1900. The equipment, too, is also old, with red copper and wooden vessels that have been used for decades and in some cases, for more than a century.

The brewery has been in the same family for four generations. Jean Van Roy, the great-grandson of the founder, runs the brewery today. It was Jean Van Roy who conceived of the Zwanze beer. You can learn more about the brewery and their beers at www.cantillon.be.

The joker

The northern half of Belgium is known as Flanders. The language spoken there is a dialect of Dutch, known by the same name as the people of Flanders: Flemish. The word zwanze is Flemish, with origins in Yiddish, and it means a self-deprecating type of humor that's typified by sharp-edged, playful jokes. It's said that this type of humor has become a characteristic trait of the Flemish themselves.

A zwanze is a joke, a zwanzer a joker, and it was with that same playful spirit that Cantillon approached the concept of making Zwanze beer. The goal was to create a fun beer, something a little unusual, using nontraditional ingredients. This year's Zwanze beer is made with rhubarb. The base beer is a lambic that has two seasons -- or summers -- in wooden barrels before being moved to a stainless-steel conditioning tank, where 300 grams of rhubarb per liter -- about two-thirds of a pound -- are added and aged for roughly three months. It is kegged directly from the tank.

The first Zwanze beer was made in 2008, and it was also a rhubarb beer. In subsequent years, they've made it with elderflowers, pineau d'aunis (a red wine grape) and, last year, coriander and orange peel, the traditional elements of a sour witbier. This is the only repeat so far, necessitated when the originally planned 2012 version -- a lambic take on a Trappist Abbey Ale -- didn't mature in time. Instead, Van Roy decided to make the rhubarb lambic again, primarily because it was his wife's favorite.

Zwanze Day at The Trappist

In addition to the Zwanze beer, The Trappist also will have kegs of two other Cantillon beers: Fou' Foune, an apricot lambic, and Lou Pepe Kriek, which is a cherry lambic that uses a sweet liquor for the second fermentation unlike most lambics, which use a young lambic for that stage in the process. Owner Chuck Stilphen says there will be Cantillon brewery memorabilia available as well.

As a huge Cantillon fan, Stilphen is understandably thrilled about the upcoming event. "I'm totally excited and fortunate to be one of the only bars in the country," he says, "so it's a great honor."

Stilphen plans to open The Trappist a little earlier than usual for Zwanze Day, probably around 11:30 a.m., but check the Trappist Insider's Facebook page, which can be accessed from its website, www.thetrappist.com. There won't be any advance sales, and it will be first come, first served.

Details: The Trappist, 460 Eighth St., Oakland

More holiday beer events

If you can't make it to Zwanze Day or you're interested in sampling more special releases, there are at least two more events worth putting on your calendar. Oakland's Pacific Coast Brewing is hosting its 24th annual "Tasting of Holiday Beers" from noon to 4 p.m. on Dec. 8. Tickets are $60 and include holiday beers and food pairings. Score sheets are provided, if you'd like to take notes. For details, visit pacificcoastbrewing.com.

The Trappist will host its annual Kerstbier Fest at 6 p.m. Dec. 14 and 15. The $25 ticket includes a commemorative glass and four 6-ounce pours, with more than 25 Belgian and other European winter and Christmas beers to choose from.